This invention relates to cylindrical shaped work members such as slitters, anvils, spacers and the like. More particularly, it relates to slitters, anvils, spacers and the like which are used to slit wide rolls of products such as paper, films and fabrics or other relatively thin materials.
Paper as a typical material is referred to herein for simplicity. When paper is manufactured at a mill, it is first formed in wide rolls which must be cut into narrower rolls by a process referred to as slitting for shipment to customers. A plurality of circular devices known as slitters are attached to a rotating shaft. Below the slitters rest so-called anvils having edges which are adjacent to, but clear of, the sharp edges of the rotating slitters. The wide web of paper passes between the edges of the slitter and the edges of the anvil whereby the paper is slit. In order for this slitting process to perform properly, the edges of the slitters must be sharpened periodically. In addition, after several sharpenings, the slitters must be replaced.
Originally, slitters were one-piece cylindrical members which were received over the shaft. When it came time to replace or sharpen a slitter, it was necessary to remove the shaft from the machine and slide the slitter off the end of the shaft. Removing the shaft from the machine required the removal of various drive belts and other parts, and replacing the belt drives and other parts when the shafts were put back in place.
More recently, two-piece slitters have been utilized so that the slitters may be removed from the shaft without the need to remove the shaft from the machine. However, it is often difficult to maintain axial and radial alignment with respect to the two halves of a two piece slitter. Misalignment of the two halves has been known to cause a poor cut, including misdirection and frayed edges on the paper.
U.S. Pat. No. 5,085,535 issued to Solberg et al teaches an improved slitter having two halves which are aligned both in the axial and radial direction. The Solberg patent, however, suffers from several deficiencies, including the fact that the halves may be put together in two different ways. Because of manufacturing variations, the two halves may fit together differently, depending on which way they are put together. Also the length of the screws and the heads of the screws which hold the halves together are located in the same half resulting in an imbalance. Therefore, there is a need to provide an improved two-piece slitter which has axial and radial alignment but which also provides a symmetrical design to enhance dynamic balancing to overcome these problems while still being commercially producible without ultra precision and high cost.
When used herein, the term slitter shall include two-piece cylindrical shaped members which may be slitters, anvils, spacers and the like which are used in the paper or film industries and which are adapted to be placed on a rotating shaft.